Nickel electrodeposition using EnFACE

In this paper, the usefulness of EnFACE “maskless” technology to transfer millimetre and micro scale features of nickel has been described. Here, electrode position was used with a patterned tool (anode) and uncoated substrate (cathode) placed in an electrochemical reactor separated by a narrow gap i.e. 300 μm. It requires resistive electrolytes with low concentration of metal ions which leads to a reduction of material and chemical usage. An electrochemical cell with a volume about 500 ml was utilised. An electrolyte of 0.19 M nickel sulfamate was chosen and shown to be capable of depositing nickel. Millimetre and micron scale feature manually fabricated as well as micron feature prepared by using photolithography were used. Current density for nickel deposition was observed to be different for each feature area. Nickel was deposited at cell potential ranging between ?2.2 and ?2.4 V. A feature of 1 mm × 5 mm and features of 300–800 μm width have been successfully transferred. An increase in dimension of the deposited feature was observed due to current spreading. The features were broader at longer processing time and for smaller feature size. A thickness up to 0.54 μm was obtained for 125–600 s at a current efficiency ranged between 50 and 90 %. EDX and XPS analysis show that the nickel deposit was metallic. SEM analysis shows that the deposited nickel was dense and compact.